IGFBP2 and melanoma: We then performed a 3D spheroid assay, in which we embedded melanoma cell spheroids in collagen with young or aged fibroblasts, in which IGFBP2 was modulated, i.e., rIGFBP2 in young fibroblasts (Fig. 3C; Supplementary Fig. S2B) or neutralizing IGFBP2 antibody in aged fibroblasts (Fig. 3C; Supplementary Fig. S2C).